This invention relates generally to devices for implementing a ground connection between a metallic shield of a cable and a common ground point. More particularly, the present invention relates generally to clamp devices which mount to service cables and connect with a common ground point.
A number of various types of devices have been employed for connecting a ground wire with the tubular ground shields of service wires. Most conventional devices employ clamp assemblies of various forms. In applications to which the present invention relates, the connecting devices are ordinarily positioned within a cabinet, housing or other enclosure, hereafter collectively termed "enclosure", to provide a grounding connection between the metallic shield of the service cable and a common ground point. Frequently, there is a minimal amount of available space within the enclosures for such ground connecting devices.
A number of conventional designs are configured to mount rigidly or semi-rigidly within the enclosures. Such conventional designs typically utilize a plurality of individual components which must be individually manufactured and assembled. Generally, such conventional designs utilize copper/tin plated steel, bronze and/or copper for the various components, depending on the strength and/or electrical properties required. Although each individual grounding device contains only a small amount of each of these materials, the relative costs of some these materials can have a significant impact on the market price of the grounding device. In addition, such devices typically clamp directly to the cable shield. Such shields are not generally designed as strength members and are easily damaged by forces transmitted to the shield by the cable clamp. Furthermore, such forces are generally concentrated along the edge of the cable clamp. Consequently, relatively minor forces may cause shearing of the cable shield.
U.S. patent application Ser. No. 08/576,446 discloses one type of cable clamp to which the present invention generally relates. The clamp has a stamped metal U-shaped body portion or yoke. A keeper threadably engages thread surfaces at the interior side of the yoke legs. The keeper has a clamp jaw which may be compressively engaged against a cable shield received in an aperture defined by the yoke. The yoke connects to a common ground point via a flexible ground wire connection or a rigid ground connection which is mounted to the yoke by a screw or rivet. A bracing portion of the rigid ground connection includes two arms which may be crimped into engagement with the cable outer jacket to relieve strain on the cable conductive sheath. Although such cable clamp is an improvement over the conventional devices, the rigid ground connection is generally composed of relatively expensive brass to provide the proper mechanical and electrical properties. Although the use of a separate rigid ground connection, yoke, and screw/rivet provides flexibility of manufacture, such separate components are relatively expensive to manufacture and assemble into a finished product.